Natures wonders: foraminifera, amazing amoebas (Introduction)

by David Turell , Wednesday, March 07, 2018, 22:18 (2451 days ago) @ David Turell

These are aquatic amoebas with shells:

"Amid the chilly waters off Antarctica lives an ancient, aquatic amoeba called Astrammina rara Barely big enough to be seen by naked eye, this creature consists of just a single cell encased within a hard shell. But that shell makes it remarkable. Using tiny, tentacle-like protrusions called pseudopodia, the amoeba builds its home by cementing together bits of sediment carefully plucked from the seafloor. Even stranger, it will only use grains of a very specific color, size and shape.

"This discerning critter is a member of the group foraminifera — amoebas that live inside shells called “tests” — and it is not the only one to show extraordinary architectural skills. Just this year researchers reported the discovery of a new kind of foraminifer that uses the shells of a second, smaller species to construct its test. The amoeba apparently selects the shells of that species even though plenty of other kinds of construction materials are available, and it arranges them in a very particular pattern.

“'This mode of construction ... seems to require either an extraordinarily selective trial-and-error process at the site of cementation or an active sensory and decision-making system within the cell,” the researchers write.

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"Not only do some forams build their own shells, many are fierce hunters, capable of snatching multicellular prey from the water column using their pseudopodia. Still others harbor algae companions, which live inside their shells and provide energy through photosynthesis. This symbiosis has allowed some forams to become positively huge; the ancient Egyptians used one extra-large group, called Nummulites, as coins. Meanwhile, humans can only marvel at the powerful organic cement they use to hold their shells together; some scientists are studying this substance in hopes of improving our own building materials.

"Charles Darwin apparently felt as Lam and I do. He was so taken with forams' engineering ability that, in an 1872 letter to his friend W.B. Carpenter, he called it “almost the most wonderful fact I ever heard of.” (This from the man who witnessed so much of life's diversity he was inspired to revolutionize the field of biology.) “One cannot believe that they have mental power enough to do so, and how any structure or kind of viscidity can lead to this result passes all understanding.”

"With due respect to Mr. Darwin, “mental power” is probably the wrong phrase to use in talking about foraminifera. With just a single cell to speak of, forams don't have a nervous system with which to make decisions — though their behaviors are complex, the mechanisms that govern them are necessarily instinctual. A foram architect is not “smart” in the same manner as a human one.

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"But, to my mind, forams are no less brilliant for their brainlessness. Like slime molds that map out metro systems, plants that form memories and ants that learned to farm, their abilities have been hard-won through generations of evolutionary trial and error. Rather than individual intelligence, they reflect a kind of general wisdom of biology: the ability of natural selection to produce creatures that are beautiful, bizarre, and uniquely equipped to fill their place in the world."

Comment: From today's Washington Post. How do they do this without brains? Did they learn this through trial and error as the author says? Their activity requires the use of information. They are not explained just like slime mold. God could have been involved.